Make-and-break electric-motor device



April l1, 1939 w. KoHLHAGr-:N 2,153,761

MAKE-'ANDBREAK ELECTRIC MOTOR DEVIF,

Filed April 4, 1958 59 @Z w l/ 17 @o 53 8130.26 f jig! Patented Apr. 11, 1939 UNITED sTATEs PATENT OFFICE to The Waterbury Clock Company, Waterbury, Conn., a corporation oi ConnecticutI Application April 4, 1938, Serial No. 199,783

iClaims.

- The present invention relates to an improvement in electric-motor devices, and particularly to that class of motor devices primarily designed for driving small tools such, for instance.vas;elec

tric dry shavers, hair-clipping devices, etc., ofV

the type wherein the energization oi' the energizing-coil is controlled by a make-jand-break device.

Heretofore, it has been proposed in motor devices of the type referred to, to divide the energizing-coil into two sections arranged coaxially side by side, in attempts to minimize high voltage transients or surges. These prior coil constructions have, however, been expensive to produce and relatively ineilicient in providing a desirable condenser action between the' two coil-sections.

The present invention contemplates a make-` and-break motor device in which at least two coil-sections are employed. but in which one coilsection is superimposed upon' and circumferentially envelopsthe other coil-section. whereby not only is the coil-structure as a whole economical to produce, but theinnermost coil-layer of the outer coil-section and the adjacent outermost coil-laye of the. inner coil-section coact' with one another to provide a much greater condenser eiiect than is feasible with energizing-coils wherein the coil-sections are not superimposed one upon the other, but are axially displaced with respect to each other. l

Furthermore, as will be seen from the following, the present invention contemplates a make-v and-break motor device in which the sections of the energizing-coil have their respective coillayers of the highest transient potential located immediately adjacent the similar layer of the other coil-section, whereby a choke coil eifect is assured, tothus minimize electrical radiation in the manner'explained below.

One of the objects ofthe vpresent invention is to provide a superior make-and-break motor device which will minimize the production ofhighvoltage electrical radiation of such character as might interfere with radio reception and the like.

A further object of the present invention is to provide a device of the character referred to, wherein the energizing-coil may be produced at a low cost for manufacture, despite the fact that it embodies two substantially-distinct coil-sections.

Another object of the present invention is to provide a superior make-and-break motor device, wherein arc'ing between the coacting contacts of the make-and-break device is reduced to a minimum.

A still further object of the present invention is to provide a device of the character referred grammatic representation of the electric circuit tok and having two coil-sections. which is characterized by superior compactness.

With the above and other objects in view, as will appear to those skilled in the art from the present disclosure, this invention includes all 5 features in the said disclosure which are novel over the prior art.

In the accompanying drawing, in which certain modes of carrying out the present invention are shown for illustrative purposes: 1o

Fig. 1 is a face view of an electric dry-shaving device embodying the make-and-break motor device .ofl the present invention, land showing one section of the casing of the said razor removed for clarity of showing;A 15

Fig. 2 is a transverse sectional view taken on the line 2--2 of Fig; 1;

Fig. 3 is a schematic view in central longitudinal section of the energizing-coil with a dia- 20 of which the said coil forms a part; and

Fig. 4 is a perspective view of the rotor, together with a portion of the drive-shaft.

The particular make-and-breakl electric motor device herein chosen for illustration includes a casingy 9 formed of two complemental hollow cas- Amay be manipulated as a unit. Within the casing t formed by the members III and Il, the

' mechanism to be presently described is installed.

An'assemblyor mounting-plate I2 is secured within the casing 0 and is preferably formed of brass or other suiiiciently-strong lnon-magnetic material. `The said plate I2 mounts a statorstructure which includesan energizing coil-structure generally designated by the reference character Il, a soft iron or steel stator-magnet generally designated by the reference character Il. 40 A laminated rotor of bipolar form and generally designated by the reference character l5 and formed of suitable magnetic4 material such as silicon steel, soft iron,`etc., is positioned to be propelled by the stator-structure, as will hereinafter appear. Thesaid stator-magnet I4 is preferably formed of suitable laminations and includes a core-portion I8 extending through the energizuing coil-structure Il and having at its respective brace the same. 66

The rotor I5 is rigidly attached to the inner end of a drive-shaft I 8 which is journaled in bearing-blocks I 3 and 2Ii mounted upon the assemblyplate I2 before. referred to. The said drive-shaft I8 is provided with a knurled starting-wheel 2I rigidly secured thereto intermediate the bearings I9 and 20, and has its outer end projected beyond the end of the casing .3, and is provided at its extreme end with an eccentric driving-pin 22 by means of which the movable cutter-member of a so-called dry shaver or any other suitable device which it is desired to operate, may be actuated.

Intermediate the bearing-block I3 and the starting-wheel 2|, the drive-shaft I3 is cut away to provide a substantially-elliptic cam-portion 23 which is adapted to engage andtwice lift for each revolution of the said drive-shaft, a pad 24 formed of suitable wear-resistant material. The pad 24 just referred to is rigidly attached to the intermediate portion of a flexible breaker-arm 25 formed of -material which has both electro-conductivity and flexibility, such for instance as spring steel, phosphor-bronze, or the like.

One end of the flexible breaker-arm 25 above referred to is rigidly attached to the outer surface of an arm 26 constituting a part of an L- shaped insulating block generally designated by the reference character 21 and including also a base-portion 28 rigidly attached to the mountingplate I2 before referred to by means of rivets 29-29. The said breaker-arm 25 is stabilized against edgewise swinging movement by having its fixed end snugly seated in a groove 30 formed in the upper end of the arm 25 of the insulatingblock 21. The said breaker-arm is clamped in place in the said groove by a screw 3| which extends downwardly through the arm 28 of the insulating-block 21 and into threaded engagement with a nut 32 formed of conduction material and located against the under-side of the said insulating-block 21 partly in a clearanceopening 33 formed in the adjacent portion of the mounting-plate I2.

At its free end the exible breaker-arm 25 is provided (Fig. 2)` with a substantially-cylindrical contact 34 which is adapted to coact with a similarly-shaped contact 35 formed at the upper end of arcontact-screw 35 threaded into a bushing or nut 31 of brass or other suitableelectroonductive material. The said nut or bushing 31 is staked or otherwise secured to a terminal-plate 38 also formed of brass or other suitable electroconductive material and rigidly attached to the upper face of the base 28 of the insulating-block 21 by means of rivets 39-33, which also extend through an insulating-plate 45 superimposed upon the upper-face of the said terminal-plate 33.

The nut or bushing 31 projects downwardly through a clearance-passage 4I in the assemblyplate I2 so as to be out of electrical engagement therewith, and has screwed into its lower end a binding-screw 42 beneath which is clamped the terminal-arm 43 of a resistor 44. The opposite terminal-arm 45 of the said resistor is clamped beneath a binding-screw 45 threaded into the lower end of the nut 32, as shown in Fig. 2. 'I'he said resistor 44 may have any suitable rating (such for instance as 25,000 ohms), and in effect, as thus connected, constitutes a shunt between the complemental contacts 34 and 35 of the breaker mechanism.

Returning now to the energizing coil-structure I3 which is schematically shown in section in Fig. 3, it will be noted by reference to the said figure that the said coil-structure is in fact composed of two coils or coil-sections, i. e., an inner coil-section or coil 41 and an outer coll or coilsection 4I.

- The inner coll-section 41 is composed of a series of superposed coil-layers 49, each separated from the other by suitable sheet insulation 50 composed of paper or other suitable material. The innermost one 43a of the coil-layers 49, Just referred to, is wound directly upon a core-tube 5I formed of impregnated cardboard or other suitable material and through which the core-portion I4 of the stator-magnet I4 extends. The inner coilsection 41 is provided at its respective opposite ends with terminal-leads 52 and 53 respectively, forming features of the inner coil-layer 49a and the outer coil-layer 45h thereof.

The outer coil-section 44.-like the inner coilsection 41, is composed of a plurality of superposed coil-layers 54 separated from each other by suitablesheet insulation 50 formed of paper or other suitable material. The inner coll-layer 54a of the outer coil-section 45 has extending from it a terminal-lead 55 constituting one of the two terminal-leads of the said outer coilsection and complemented by aterminal-lead 54 which is at the opposite end of the coil-section 44 from the terminal-lead 55 and constitutes the electrical terminal of the outer coil-layer 54b of the said outer coil-section 4I.

Inasmuch, as will hereinafter appear, the outer coll-layer 43h of the inner coll-section 41 and the inner coil-layer 54a of the outer coil-section 44 are the layers between which the greatest potential diiference exists,it is preferred, as shown in Fig. 3, to lnterpose between the said coil-layers and hence between the said coil-sections, a relatively-heavy insulating layer 51, preferably made of varnished cambric or the like.

As before pointed out, the showing of Fig. 3 is schematic in character and it may here be stated that the number of coil-layers, the number of turns in each layer, and other factors, will be varied to meet a given set of requirements in accordance with well understood principles in the art. By way of example of a specific structure, it may be said that the respective coil-sections 41 and 4l may. for instance, each be composed of twelve hundred and fifty turns of No. 37 enameled copper wire.

As is illustrated particularly well in Fig. 1. the terminal-lead 52 of the inner coll-section 41 is connected at 52a by solder or {any other suitable means to a line-wire 5I leading out ofl the casing or housing l to one prong 59 of a plug 50 indicated in Fig. 1A and adapted to be inserted into a usual electric outlet. The terrninal-lead 50 of the outer coil-section 44 is soldered or otherwise secured as at 55a to a second line-wire 5I leading out of the casing-members I0 and II to the remaining prong 42 of the plug 40, before referred to.

The remaining terminal 53 o f the inner coilsection 41 extends to and is clamped beneath the head of the screw 3| which holds the flexible breaker-arm 25 in place on the arm 25 of the insulating-block 21. Thus, the said terminallead 53 is placed in electrical communication withl not only the contact 34 at the free end of the breaker-arm 25, but also with the terminal-arm 45 of the resistor 44.

The remaining lead 55 of the outer coll-section 43 is soldered or otherwise secured to the terminal-plate 35 so as to be in electrical communication with not only the stationary contact 35 of the circuit breaker, but also the terminal-arm 4I of the resistor 44.

It will be apparent from the foregoing and the accompanying drawing that the two coil-sections 41 and 48 are electrically connected in series when the movable contact 34 is in engagement with the stationary contact 35, and further, that the connections are such that one of the said coil-sections is always electrically interposed between a given one of the contacts 34 or Il and a given one of the line-wires.

As thus connected, it will also be apparent that with respect to the entire coil-structure il, the highest transient voltages or potentials will exist between the outer coil-layer 4Gb of the inner coilsection 41 and the inner coil-layer 54a of the outer coll-section 48.

In winding the energizing coil-structure Il, the respective inner and outer coil-sections 41 and 48 thereof may be wound as a unit. Preferably, the inner coil-layer 49a. of the inner coil-section 41 is first wound upon the core-tube 5I starting at substantially the point of the terminal-lead 52 thereof and continued in successive coil-layers 48 until the outer coil-layer 49h of the inner coilsection 41 is completed, whereupon the winding may be continued for one or more extra turns or coils beyond the normal termination point of the said coil-layer and then resumed back again over the outer surface of the varni'shed-cambric insulating-layer i1 to complete the outer coil-section 48. The two said coil-sections will thus be left in direct electrical interconnection. One or more of the turns of the coil-layer 48h and the coil-layer 64a may be drawn outwardly to form the terminal-leads 58 and 5l respectively of the inner and'uter coil-sections 41 and 48. The said terminal-leads 53 and` 55 will at this stage in the process of manufacture be continuous by the portion of wirefndicated by the broken line 8.8 in Fig. 3. The severing orcuttlng away of the wireportion indicated at l8`wi1l serve toelectricaily isolate the twocoil-sections 41 and 48 and result in they formau 'of the two termina-leads u' .and 58.

In the operation of the motor device above described, the drive-shaft Il will be first manually started, whereupon the cam-portion 28 of the said drive-shaft I8 will function to operate or flex the breaker-arm 28 to move the contact 34 into and out of engagement with the contact 3E twice for each revolution of the said driveshaft, so that the energizing-coil structure I8 y has current delivered to it by the engagement of the said contacts at properly-timed intervals to maintain the rotor I8 in operation.

The plug 80, before referred to, may be plugged into anoutlet of either an alternating-current system or a direct-current system of comercial voltage, since the motor device, owing to the action of its mechanically-operated circuitbreaker, will operate with substantially the same efficiency with either an A. C. or D. C. current supply.

The minimizing of electromagnetic radiation, according tothe present invention, depends upon the concentration of at least the major portion of, the capacity-effects of the coil between the adjacently disposed innermost coil-layer of an I outer coil-section and the outermost coil-layer tion of at least one coil-layer having relatively high choke-coil-efi'ect, between each of the first said coil-layers and the line-terminal of the coilscction in which it is included. For this purpose, according to the present invention, one of the coil-sections is arranged in circumferentiallyenveloping relation to the other and separated therefrom by an interposed dielectric throughout the common length of the coil-sections in such a way that the inner limb of the electromagnetic field of the outer coil-section extends longitudinally of the coil inside of the cylindrical dielectric while the outer limb of the .electromagnetic field Aol' the inner coil-section extends longitudinally of the coil on the outsid of the said dielectric. Due to the opposite polarities of the trans-dielectric limbs of the electromagnetic circuits of the inner and outer coilsections, the capacity effects between the inner and outer coil-sections will be mainly concentrated between the innermost coil-layer of the outer coil-section and the outermost coil-layer of the inner coil-section. In consequence, each of the said limbs of the electromagnetic fields of both coll-sections are arranged in blanketed relation to the other while the said coil-layers of both coil-sections between which thecapaoity `effects are mainly confined, are arranged on opposite sides of the make-and-break device for,

the motor. At the same time, while the capacity effects in applicants coil are largely or mainly concentrated between the innermost coll-layer of the outer coil-section and the outermost coillayer of the inner coil-section, the capacity ei'- fects in the coil-layers adjacent the outer circumference of the outer coil-section and the inner'circumference of the inner coil-section are comparatively small. Inasmuch as there is considerable inductance in these coil-layers irnmedlately adjacent the line-terminals and in the absence of any considerable neutralizing effects of capacitance thereon, the last-mentioned coil-layers provide effective choke-coil-effects. It is to be noted, furthermore, that applicants coil comprises an arrangement of the coil-sections in such a way that each 'is interposed between the other and a line-terminal, and that each coilsection contains, at least, one coil-layer having considerable inductive effects and very little intercapacity effects, interposed between one of the high transient 4potential coil-layers at the dielectric and each line-terminal.

In virtue of this construction, high voltage surges conveyed to the coil from the line-wires as well as high potential kickbacks due to capacitance, are suppressed or minimized by, the choke-coil-effects in the coil-layers adjacent the line terminal with a resultant dampening of electromagnetic radiation of radio frequencies which, in large measure, is -suppressed within the coil-sections.

From the foregoing, it will be seen that by superimposing the coil-secton 48 or its equivalent upon and causing the same to circumferentially surround the inner coil-section 41 or its equivalent, a maximum condenser effect is secured between the respective coil-sections over substantially their entire length. In this manner, the electrical radiation which would ordinarily occur from transient potentials is conflned mainly within the coil-structure itself. Thus, electrical radiation which might interfere with radio reception or the like is so minimized or suppressed as not to materially affect other electrical apparatus. Furthermore, the construction and arrangement of parts, above described, serves to minimize arcing between the complemental contacts 34 and J5.

One of the salient features, therefore, of the present invention is the particular arrangement of the two coil-sections, so that one thereof is superimposed upon and circumferentially surlrounds the other in contradistinction to coilstructures wherein two coil-sections are mounted end to end in relative axial displacement.

Preferably and as shown, the resistor M is connected to the breaker-contacts 34 and 35 to minimize .voltage surges which might occur as the contacts 34 and 35 are separated one from the other in the operation of the device. Ines' much as the coil-structure I3, when the device is in operation, provides both inductance and capacitance which coact with each other to produce what is commonly referred to as resonance, it is preferred to employ the resistor 44 to minimize or subdue such resonance.

.The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative fand not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim:

1. An electric-motor device, comprising: a held-magnet member having salient poles; a rotor positioned to be propelled by the magnetic ux from the said field-magnet member; an energizing coil-structure for the said field-magnet member; and a circuit-breaker operatively connected to the said rotor for being actuated `thereby, and having two cooperating relativelymovable contacts; the said energizing coil-structure having an inner coil-section provided with two terminals and an outer coil-section also provided with two terminals and superimposed upon and circumferentially surrounding the exterior of the said inner coil-section; one of the terminals of the said inner coil-section being electrically connected to one of thesaid cooperating contacts of the said circuit-breaker, and one of the said terminals of the said outer coil-section being electrically connected to the other of the said cooperating contacts of the said circuitbreaker, the .remaining terminal of each of the said coil-sections being connectable to a source of electrical energy.

2. An electric-motor device, comprising: a field-magnet member having salient poles; .a rotor positioned to be propelled by the magnetic ux from the said field-magnet member; an energizing coil-structure for the said field-magnet member; a circuit-breaker operatively connected to the said rotor for being actuated thereby, and having two cooperating relatively-movable contacts; the said energizing coil-structure having an inner coil-section provided with two terminals and an outer coil-section also provided with two terminals and superimposedupon and circumi'erentially surrounding the exterior of the said inner coil-section; one of the terminals of the said inner coil-section being electrically connected to one of the said cooperating contacts field-magnet member -having salient poles; a

rotor positioned to be propelled by the magnetic flux from the said field-magnet member; an energizing coil-structure for the said field-magnet member; a circuit-breaker operatively connected to the said rotor for being actuated thereby, and having two cooperating relatively-movable contacts; the said energizing coil-structure having an inner coil-section comprising a plurality of coil-layers superimposed one upon an- Vother, and an outer coil-section also composed of a plurality of superimposed coil-layers, the

innermost coil-layer of the said outer coil-section and the outermost layer o1' the said inner coilsection extending in parallelism with each other and with the axis ot the coil-structure and in substantial radial alignment; electrical conducting-means electrically connecting the innermost coil-layer of the said outer coil-section with one of the contacts of the said circuit-breaker; and electrical conducting-means electrically connecting the outermost coll-layer of the said inner coil-section with the other contacto! the circuitbreaker, the outer coil-layer of the said outer coil-section and the inner coil-layer of the said inner coil-section being connectable to a source of electrical energy.

4. An electric-motor device, comprising: a eld-magnet member having salient poles; a rotor positioned to be propelled by the magnetic ux from the said field-magnet member; an energizing coil-structure tor the said field-magnet member; a circuit-breaker operatively connected to the said rotor for being actuated thereby. and having two cooperating relatively-movable contacts; the said energizing coil-structure having an inner coil-section comprising a plurality of coil-layers superimposed one upon another. and an outer coil-section also composed of a plurality ofsuperimposed coil-layers, the innermost coil-layer oi' the said outer coil-section and the outermost layer o! the said inner coilsection extending in parallelism with each other and with the axis of the coil-structure and in substantial radial alignment; electrical conducting-means electrically connecting the innermost coil-layer of the said outer coil-section with one of the contacts of the said circuit-breaker; electrical conducting-means electrically connecting the outermost coil-layer of the said inner coilsection with the other contact of the circuitbreaker, the outer coil-laye: of the said outer coil-section and the inner coil-layer of the said inner coil-section being connectable to a source of electrical energy; and a resistor electrically interconnecting the inner coil-layer o! the said outer coil-section and the outer coil-layer of the said inner coil-section.

WALTER KOIniI-IAGEN. 

